1. Field of the Invention
The present invention relates to a filler neck for a fuel tank, in particular filler necks for a fuel tank of a motor vehicle, which prevent incorrect fueling with an incorrect fuel type.
2. Description of the Background Art
Motor vehicles, for example, automobiles or transport vehicles, can be operated with gasoline or diesel depending on a type of installed internal combustion engine. In the event of incorrect fueling, for example, when a diesel vehicle is fueled with gasoline, considerable damage can be caused to the vehicle during the operation of the vehicle. Furthermore, substantial costs can be incurred by emptying the fuel system after an incorrect fueling.
Diesel tank filler necks of today's automobiles usually have an opening for the hose nozzle of more than 23 mm. A spout of a diesel hose nozzle has an outer diameter of approx. 23 mm. A spout of a gasoline hose nozzle has a smaller outer diameter than the diesel hose nozzle. In the case of gas tank filler necks, the opening diameter is only a few millimeters larger than the outer diameter of the gasoline hose nozzle. The opening of the gasoline tank filler neck is 20 mm, for example. Thus only a gasoline hose nozzle fits into the opening of the gasoline tank filler neck, whereby an incorrect fueling of the gasoline vehicle can be prevented. On the other hand, diesel hose nozzles as well as gasoline hose nozzles fit into the opening of the diesel tank filler neck.
In the prior art, therefore a plurality of methods and devices are known which are designed to prevent an incorrect fueling of a diesel vehicle with gasoline.
DE 10 2005 010 530 A1, for example, relates to a warning device for fueling vehicles with the correct fuel. The device comprises a transmitter, for example, an RFID chip, and a reader device. The transmitter is attached to the vehicle and the receiver is attached to a fueling device. When the fueling device approaches the vehicle, the fuel type stored in the transmitter is compared to the fuel of the fuel type that is stored in the reader device. If the fuel is identical, a green light-emitting diode is illuminated. If the fuel is not identical, a red light-emitting diode is illuminated. If the fueling represents a hazard, e.g., gasoline and diesel have been interchanged, an acoustic alarm and a vibration alarm in the reader device are triggered.
DE 10 2009 009 998 A1, which corresponds to US 20110315682, relates to a safety element for a diesel fuel tank to prevent adding the wrong fuel. An insert element for a diesel fuel tank can be installed in the filling opening of the tank for the purpose of a hose nozzle fueling with diesel fuel at the gas station side. The insert element has an elongated tubular securing element which can be fitted into the container opening with an inlet side and an outlet side, in which a molded part, which is elongated parallel to the securing element, is secured, the free end side of which projecting towards the inlet side in the outer diameter on the one hand is smaller than the inner diameter of the spout of a diesel hose nozzle, but on the other hand is larger than the inner diameter of a gas pump nozzle spout. Furthermore, an actuation element which can be displaced coaxially to the filling opening on the inner wall of the securing element is provided, which actuation element is arranged set back behind the end side of the molded part in the direction of the interior of the tank and is capable, when displaced in the direction of the interior of the tank, of actuating a closure flap which is arranged on the outlet side of the securing element.
DE 10 2008 039 150 A1 relates to a safety element for a diesel fuel tank for preventing incorrect fueling. A tubular molded part is provided, the outer diameter of which on the one hand is smaller than the inner diameter of a spout of a diesel pump nozzle, but on the other hand is larger than the inner diameter of a gas pump nozzle spout.
DE 10 2009 049 482 A1 relates to a diesel tank adapter. The diesel tank adapter functions such that the hose nozzle is pushed over a tank neck. The tank neck is thus inserted into the hose nozzle. The diesel tank adapter prevents an incorrect fueling with gasoline by utilizing the different diameters of the two types of hose nozzle.
DE 10 2009 056 512 A1 relates to a filling system for a fuel tank. The filling system has a filling opening and a blocking device for filler pipes provided for the filling opening, which blocking device in its design differs from that of a target filler pipe for a specific fluid. The blocking device has a blocking insert, which comprises a plug-on mandrel matching the target filler pipe and movable in a path-limited manner to the filling opening for the target filler pipe.
DE 10 2008 027 462 A1 relates to an insert element for a fuel tank, which is designed for filling with diesel fuels. The accidental filling of gasoline into the fuel tank can be prevented by means of the insert. The device has an inner flank, the one end of which is wider than the standardized inner diameter of a spout provided for gasoline pump nozzles, but smaller than the standardized inner diameter of a spout provided for diesel fuel pump nozzles.
With the protection against incorrect fueling known from the conventional art with the detection of the inner diameter of the spout of the hose nozzle, such as is known, for example, from DE 10 2009 009 998 A1 or DE 10 2008 027 462 A1, with shut-off mechanisms of the hose nozzle located in the spout, collisions can occur between the shut-off mechanism and the blocking element of the protection against incorrect fueling.
FIG. 1 shows diagrammatically a conventional filler neck 1 with a filler pipe 2 and a blade-like blocking element 3 arranged therein. Furthermore, FIG. 1 shows a cross-sectional view of a spout 4 of a hose nozzle with a shut-off mechanism 5 located in the spout 4. Depending on the position of the shut-off mechanism 5 on the inside of the spout 4 and depending on the insert angle of the spout 4 into the filler pipe 2, collisions can occur between the shut-off mechanism 5 and the blocking element 3. FIG. 2 shows a lateral cross-sectional view of the filler neck 1 and the spout 4 with the shut-off mechanism 5 arranged therein. FIGS. 3 and 4 show the collision situation, in which the shut-off mechanism 5 knocks against the blocking element 3, whereby an insertion of the spout 4 into the filler pipe 2 is prevented. FIG. 3 shows a cross-sectional view of the filler neck 1 and of the spout 4 and FIG. 4 shows a lateral cross-sectional view of the filler neck 1 and of the spout 4.
Although the position of the shut-off mechanism 5 inside the spout 4 is fixed, depending on a rotation angle with which a user tries to insert the spout 4 of the pump nozzle into the tank filler neck 1, the shut-off mechanism 5 can be located at any desired position based on the blocking element 3. A twisting of the spout 4 can occur in particular when the vehicle is not oriented optimally to the gas pump and the hose is guided over the vehicle or around the vehicle, for example, between the gas pump and the pump nozzle, whereby the pump nozzle is used in a correspondingly twisted manner.